php - undefined variable : delete in C:\xampp\htdocs\xampp\Test\HRMS\try\search1. php 第 61 行

Question

在过去的 2 个小时里，我非常努力地尝试，但我无法理解。为什么我在 DELETE 中得到 undefined variable 。请查看我的代码并帮助我。

我的主要目的是使用复选框一次删除多行。

当我尝试运行以下代码时，出现以下错误:

Undefined variable: delete in C:\xampp\htdocs\xampp\Test\HRMS\try\search1.php on line 61

但我已经通过以下方式使用了它:

<td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>

提前致谢。

我的 php 代码:

  <?php
  $host="localhost"; // Host name
  $username="a"; // Mysql username
  $password="a"; // Mysql password
  $db_name="b"; // Database name
  $tbl_name="emp_info"; // Table name

  // Connect to server and select databse.
  mysql_connect("$host", "$username", "$password")or die("cannot connect");
  mysql_select_db("$db_name")or die("cannot select DB");

  $sql="SELECT * FROM $tbl_name";
  $result=mysql_query($sql);

  $count=mysql_num_rows($result);

  ?>
  <table width="400" border="0" cellspacing="1" cellpadding="0">
  <tr>
  <td><form name="form1" method="post" action="">
  <table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
  <tr>
  <td bgcolor="#FFFFFF">&nbsp;</td>
  <td colspan="4" bgcolor="#FFFFFF"><strong>Delete multiple rows in mysql</strong> </td>
  </tr>
  <tr>
  <td align="center" bgcolor="#FFFFFF">#</td>
  <td align="center" bgcolor="#FFFFFF"><strong>Id</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Name</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Password</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Address</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Source</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>salary</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Zip</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Mobile</strong></td>
  <td align="center" bgcolor="#FFFFFF"><strong>Email</strong></td>
  </tr>
  <?php
  while($rows=mysql_fetch_array($result)){
  ?>
  <tr>
  <td align="center" bgcolor="#FFFFFF"><input name="checkbox[]" type="checkbox" id="checkbox[]" value="<? echo $rows['eid']; ?>"></td>
  <td bgcolor="#FFFFFF"><? echo $rows['eid']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['ename']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['password']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['address']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['source']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['salary']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['zip']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['mobile']; ?></td>
  <td bgcolor="#FFFFFF"><? echo $rows['email']; ?></td>
  </tr>
  <?php
  }
  ?>
  <tr>
  <td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
  </tr>
  <?php
  // Check if delete button active, start this
  if($delete){
  for($i=0;$i<$count;$i++){
  $del_id = $checkbox[$i];
  $sql = "DELETE FROM $tbl_name WHERE eid='$del_id'";
  $result = mysql_query($sql);
  }

  // if successful redirect to search1.php
  if($result){
  echo "<meta http-equiv=\"refresh\" content=\"0;URL=search1.php\">";
  }
  }
  mysql_close();
  ?>
  </table>
  </form>
  </td>
  </tr>
  </table>

Answer 1

Register globals 已关闭(这很好)所以行

if($delete){

应该是

if (isset($_POST['delete'])) { ...

此外，您需要重构代码，因为当您有删除记录的发布请求时，绝对没有必要对数据库进行选择查询。

这是您需要的完整代码。只需用这个替换您的即可。

<?php

error_reporting(E_ALL);

$host = "localhost"; // Host name
$username = "a"; // Mysql username
$password = "a"; // Mysql password
$db_name = "b"; // Database name
$tbl_name = "emp_info"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// Delete records
if (isset($_POST['delete']))
{
    // Concatenate ids in a comma-separated string
    $ids = implode(',', $_POST['checkbox']);

    if (!empty($ids))
    {
        $sql = "DELETE FROM $tbl_name WHERE eid IN ($ids)";
        $result = mysql_query($sql) or die(mysql_error());
    }

    // Redirect back
    header('Location: search1.php');
    die();
}

// Select records
$sql = "SELECT * FROM $tbl_name";
$result = mysql_query($sql);

$count = mysql_num_rows($result);

?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
    <tr>
        <td>
            <form name="form1" method="post" action="">
                <table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
                    <tr>
                        <td bgcolor="#FFFFFF">&nbsp;</td>
                        <td colspan="4" bgcolor="#FFFFFF"><strong>Delete multiple rows in mysql</strong></td>
                    </tr>
                    <tr>
                        <td align="center" bgcolor="#FFFFFF">#</td>
                        <td align="center" bgcolor="#FFFFFF"><strong>Id</strong></td>
                        <td align="center" bgcolor="#FFFFFF"><strong>Name</strong></td>
                    </tr>
                    <?php while ($rows = mysql_fetch_array($result)) { ?>
                    <tr>
                        <td align="center" bgcolor="#FFFFFF">
                            <input name="checkbox[]" type="checkbox" id="checkbox[]"
                                   value="<?php echo $rows['eid']; ?>">
                        </td>
                        <td bgcolor="#FFFFFF"><?php echo $rows['eid']; ?></td>
                        <td bgcolor="#FFFFFF"><?php echo $rows['ename']; ?></td>
                    </tr>
                    <?php } ?>
                    <tr>
                        <td colspan="5" align="center" bgcolor="#FFFFFF">
                            <input name="delete" type="submit" id="delete" value="Delete">
                        </td>
                    </tr>
                </table>
            </form>
        </td>
    </tr>
</table>